This is not intended as a flame or a trolling attempt, but I'll open my post by admiting that I am one of the people who generally pushes assassins out of my groups. I don't know what assassin brings to the table, except for a lot of bad players who drain valuable monking resources. I also don't know how to tell if an assassin is at least minimally compitent. Because of that I take other classes that I actually can predict. I now that it's hard to find a group for assassins, but until I'm able to be reasonably sure that the assassin I am adding will pull his weight, I'll keep inviting other classes ( or even henchmen).
so, here's what woud make me change my mind ( as well, I expect most other people's minds.):
1. a list of 1-3 things that assassisn do better than any one else or extremely valuable thigns that they do almost as well, and an explanation of why I'd want an assassin doing it instead of whatever classes normally do it.
2. the names of the cookie cutter builds ( PUGS are all about the cookie cutter :P ) that let assassins shine at the above task(s), as well as a basic summary how they work.
3. a few questions and answers to ask an assassin that whow whether or not they are any good. ( ie what is your build and how do you see your role in the group?)
anyhow, those 3 things would make it so that I know what I can expect from an assassin (and how to weed out the majority of complete incompitants) and thus fit them into my groups when appropriate.
E

Just a wild guess...